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| Study on the application of different strength criteria for different lithology failure strength |
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Received:March 26, 2020
Revised:April 01, 2020
Accepted:April 09, 2020
Published Online:January 29, 2021
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| DOI： |
| KeyWord:strength criterion;Sandstone; Coal; Marble; Granite |
| Author | Institution |
| ZHWNG Xiaojuan |
School of Management,Jiaozuo Teachers College,Jiaozuo |
| WANG Yunfei |
School of civil engineering Henan Polytechnic university,Jiaozuo |
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| Abstract: |
| Analyzing the characteristics of strength of Coal,Sandstone, Marble and Granite under conventional triaxial test, according to the overall minimum fitting error of square root identified the parameters of 4 strength criteria, comparing the difference of the overall fitting precision of various strength criteria and the difference between experiment strengths and prediction values of compressive strengths of various strength criteria. Obtaining the following main research conclusions: considering from the overall fitting precision, the linear Mohr-Coulomb criterion fitting precision is the worst, while the nonlinear Bieniawski and Exponential strength criteria have obvious advantages on the fitting precision of different lithology strength. Mohr-Coulomb criteria overestimates the uniaxial compressive strength of different lithology, and the overestimation degree of Coal and Sandstone reaches about 50%, its prediction results is serious distortion, therefore does not recommend using Mohr-Coulomb criteria to predict the uniaxial compressive strength. The nonlinear characteristics of different lithology varies greatly in the brittle failure stage, the nonlinear characteristics of Coal and Sandstone is more significant than Granite and Marble. At the brittle failure stage, linear Mohr-Coulomb criteria has the characteristics of low confining pressure underestimating rock strength and high confining pressure overestimating. The prediction values of Bieniawski and Exponential strength criteria are consistent with the large number of experimental data, the prediction precision is the best. In general, the confining pressure effect coefficient decreases with confining pressure increasing, it decreases rapidly under lower confining pressure range, the confining pressure influence coefficient gradually trends to a constant value with it increasing. The increasing of soft rock strength effected by the confining pressure is more significant than hard rock. |
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